One of the surprising aspects of the "spontaneous" events of 13 May is that so many people were informed about what was going to happen, and nothing was done to stop it. On the 12th, the correspondent of Le Figaro had cabled back to Paris: "It is probable that tomorrow afternoon the Gouvernement-Général will be invaded by the mob." Returning from Paris that same day, the former secretary-general of the Algiers police, Paul Teitgen, warned an impassively disbelieving Salan of the impending invasion, telling him that the paras would do nothing to stop it. He then sent a warning to Pflimlin, via the curiously circuitous route of the United States consul-general, the State Department and the Quai d'Orsay. But by the time it reached Paris it would be too late in any case.

XREF: Connects to the classic pattern of intelligence warnings ignored before political upheavals, as in Pearl Harbor or the 9/11 memo.

Horne, Alistair, A Savage War of Peace- Alge…, loc. 866